US20240142898A1 - Image forming device - Google Patents
Image forming device Download PDFInfo
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- US20240142898A1 US20240142898A1 US18/381,827 US202318381827A US2024142898A1 US 20240142898 A1 US20240142898 A1 US 20240142898A1 US 202318381827 A US202318381827 A US 202318381827A US 2024142898 A1 US2024142898 A1 US 2024142898A1
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- Prior art keywords
- intermediate transfer
- cam
- transfer belt
- transfer roller
- forming device
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- 230000007246 mechanism Effects 0.000 claims abstract description 26
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- 238000003825 pressing Methods 0.000 description 35
- 238000010586 diagram Methods 0.000 description 23
- 238000012986 modification Methods 0.000 description 18
- 230000004048 modification Effects 0.000 description 18
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- 238000004140 cleaning Methods 0.000 description 6
- 239000003086 colorant Substances 0.000 description 6
- 238000012545 processing Methods 0.000 description 4
- 230000008859 change Effects 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 239000013013 elastic material Substances 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 229920002943 EPDM rubber Polymers 0.000 description 1
- JOYRKODLDBILNP-UHFFFAOYSA-N Ethyl urethane Chemical compound CCOC(N)=O JOYRKODLDBILNP-UHFFFAOYSA-N 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
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- 239000011521 glass Substances 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
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Images
Classifications
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G15/00—Apparatus for electrographic processes using a charge pattern
- G03G15/14—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base
- G03G15/16—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base of a toner pattern, e.g. a powder pattern, e.g. magnetic transfer
- G03G15/1605—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base of a toner pattern, e.g. a powder pattern, e.g. magnetic transfer using at least one intermediate support
- G03G15/1615—Apparatus for electrographic processes using a charge pattern for transferring a pattern to a second base of a toner pattern, e.g. a powder pattern, e.g. magnetic transfer using at least one intermediate support relating to the driving mechanism for the intermediate support, e.g. gears, couplings, belt tensioning
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G15/00—Apparatus for electrographic processes using a charge pattern
- G03G15/01—Apparatus for electrographic processes using a charge pattern for producing multicoloured copies
- G03G15/0105—Details of unit
- G03G15/0131—Details of unit for transferring a pattern to a second base
- G03G15/0136—Details of unit for transferring a pattern to a second base transfer member separable from recording member or vice versa, mode switching
Definitions
- the present disclosure relates to an image forming device.
- an image forming device including a transfer device that transfers a toner image from an image carrier to a paper sheet via an intermediate transfer belt.
- the transfer device is provided with a transfer roller that can be displaced in a direction that makes contact with, and separates from, the image carrier.
- An object of the present disclosure is to provide an image forming device that enables an impact sound generated when an image carrier is pressed by a presser to be suppressed.
- An image forming device includes: one or more image carriers on which a toner image is formed; a transfer belt that transfers a toner image formed on the image carrier; a presser that presses the transfer belt against the image carrier to transfer the toner image onto the transfer belt; and a switching mechanism that switches a position of the presser according to a rotation angle of a cam; wherein the switching mechanism switches a position of the presser to one of a first position that presses the transfer belt against the image carrier, a second position that is separated from the image carrier, and a third position that is a position separated from the image carrier and having a smaller separation distance from the image carrier than the second position.
- an image forming device is capable of suppressing an impact sound generated when an image carrier is pressed by a presser.
- FIG. 1 is a schematic diagram showing an example of an internal structure of an image forming device according to an embodiment of the present disclosure.
- FIG. 2 is a diagram schematically showing an example of a configuration when all of the intermediate transfer rollers provided in an intermediate transfer belt unit according to the embodiment of the present disclosure are in a separated position.
- FIG. 3 is a diagram schematically showing an example of a configuration when the intermediate transfer rollers provided in the intermediate transfer belt unit according to the embodiment of the present disclosure are in a pressing position and a retracted position.
- FIG. 4 is a diagram schematically showing an example of a configuration when all of the intermediate transfer rollers provided in the intermediate transfer belt unit according to the embodiment of the present disclosure are in the pressing position.
- FIG. 5 is a diagram schematically showing an example of a configuration when all of the intermediate transfer rollers provided in the intermediate transfer belt unit according to the embodiment of the present disclosure are in the retracted position.
- FIG. 6 is a plan view of the intermediate transfer belt unit shown in FIG. 2 .
- FIG. 7 is a schematic diagram showing an example of the main components of a first swing member included in the intermediate transfer belt unit according to the embodiment of the present disclosure.
- FIG. 8 is a schematic diagram showing an example of the main components of a first swing member included in the intermediate transfer belt unit according to the embodiment of the present disclosure.
- FIG. 9 is a diagram showing an example of the configuration of a cam included in the intermediate transfer belt unit according to the embodiment of the present disclosure.
- FIG. 10 is a diagram showing an example of a first cam of the cam shown in FIG. 9 .
- FIG. 11 is a diagram showing an example of a second cam of the cam shown in FIG. 9 .
- FIG. 12 is a table showing a correspondence relationship between the rotation angle of the cam included in the intermediate transfer belt unit according to the embodiment of the present disclosure, the operation state of the image forming device, the position of a first intermediate transfer roller, and the position of a second intermediate transfer roller to fourth intermediate transfer roller.
- FIG. 13 is a diagram showing an example of a cam included in an intermediate transfer belt unit according to a modification of the embodiment of the present disclosure.
- FIG. 14 is a table showing a correspondence relationship between the rotation angle of the cam included in the intermediate transfer belt unit according to the modification of the embodiment of the present disclosure, the operation state of the image forming device, the position of a first intermediate transfer roller, and the position of a second intermediate transfer roller to fourth intermediate transfer roller.
- FIG. 1 is a schematic diagram showing an example of an internal structure of an image forming device 100 according to the embodiment of the present disclosure.
- FIG. 1 is a diagram of the internal structure of the image forming device 100 when viewed from the front side.
- the left side is defined as the left direction
- the right side is defined as the right direction.
- the front side (near side) of the image forming device 100 is defined as the front direction
- the rear side (far side) is defined as the rear direction.
- the bottom side is defined as the downward direction
- the opposite side is defined as the upward direction.
- the image forming device 100 is a laser color printer that forms multicolor and monochrome images on a paper sheet on which an image is formed.
- the image forming device 100 prints an image on a paper sheet based on image data read from a document by an image reading device 90 , or image data received from an external source. Note that, although a laser color printer is described as an example of the image forming device 100 in the present embodiment, the present disclosure is not limited to this.
- the image forming device 100 includes a printer 110 , an image reading device 90 , a document table 92 , and an automatic document processing device 120 .
- the printer 110 includes an exposure unit 1 , developers 2 , photoreceptor drums 3 a to 3 d (image carriers), cleaner units 4 , chargers 5 , an intermediate transfer belt unit 6 , a fusing unit 7 , a paper feeding cassette 81 , and a manual paper feeding cassette 82 .
- the photoreceptor drums 3 a to 3 d are simply referred to as the photoreceptor drums 3 when there is no need for the description to distinguish between them.
- the upper part of the printer 110 is provided with the image reading device 90 and the document table 92 , which is made of transparent glass. Furthermore, the automatic document processing device 120 is installed on the upper side of the document table 92 .
- the automatic document processing device 120 automatically transports a document onto the document table 92 . Moreover, the automatic document processing device 120 is configured so as to be rotatable in the direction of arrow R. Further, a document can be placed on the document table 92 by opening the top of the document table 92 .
- the image reading device 90 reads image data from a document transported or placed on the document table 92 .
- the printer 110 prints an image on a paper sheet based on the image data read by the image reading device 90 .
- the image data handled by the image forming device 100 corresponds to a color image that uses each of cyan (C), magenta (M), yellow (Y), and black (K) colors. Accordingly, the developers 2 , the photoreceptor drums 3 , the cleaner units 4 , and the chargers 5 are each provided so as to form four types of latent images corresponding to the respective colors.
- the chargers 5 uniformly charge the surfaces of the photoreceptor drums 3 to a predetermined potential.
- the chargers 5 may be charger type, contact type, or brush type chargers or the like.
- the exposure unit 1 is configured as a laser scanning unit (LSU) provided with a laser emitter, a reflecting mirror, and the like.
- the exposure unit 1 includes polygon mirrors for performing scanning with a laser beam, and optical components, such as lenses or mirrors, for guiding the laser beam reflected by the polygon mirrors to the photoreceptor drums 3 .
- the exposure unit 1 exposes the charged photoreceptor drums 3 according to the image data to form electrostatic latent images corresponding to the image data on the surfaces of the photoreceptor drums 3 .
- the developers 2 visualize the electrostatic latent images formed on the photoreceptor drums 3 using toner.
- the toner images are formed on the photoreceptor drums 3 as a result of being visualized with toner.
- the developers 2 include developer tanks 2 a , and the toner is accommodated in the developer tanks 2 a .
- the developers 2 are configured to supply the toner accommodated in the developer tanks 2 a to the photoreceptor drums 3 .
- the developer tanks 2 a are connected to toner cartridges 8 that accommodate the toner via toner supply pipes (not shown).
- the toner cartridges 8 are provided for each of the four toner colors.
- the cleaner units 4 remove and collect the residual toner remaining on the surfaces of the photoreceptor drums 3 after development and image transfer.
- the intermediate transfer belt unit 6 is disposed above the photoreceptor drums 3 .
- the intermediate transfer belt unit 6 includes an intermediate transfer belt 61 (transfer belt), an intermediate transfer belt drive roller 62 , an intermediate transfer belt driven roller 63 , a first intermediate transfer roller 64 a to fourth intermediate transfer roller 64 d (pressers), and an intermediate transfer belt cleaning unit 65 .
- the first intermediate transfer roller 64 a to fourth intermediate transfer roller 64 d are provided corresponding to the respective colors of K, Y, M, and C. Note that the first intermediate transfer roller 64 a to fourth intermediate transfer roller 64 d are simply referred to as the intermediate transfer rollers 64 when there is no need for the description to distinguish between them.
- the intermediate transfer belt drive roller 62 , the intermediate transfer belt driven roller 63 , and the first intermediate transfer roller 64 a to fourth intermediate transfer roller 64 d each stretch and rotationally drive the intermediate transfer belt 61 .
- the intermediate transfer rollers 64 apply a transfer bias for transferring the toner images of the photoreceptor drums 3 onto the intermediate transfer belt 61 , and also press the photoreceptor drums 3 .
- the position in which the intermediate transfer rollers 64 press the photoreceptor drums 3 via the intermediate transfer belt 61 is referred to as the pressing position (first position).
- the intermediate transfer belt unit 6 further includes a movement mechanism 20 (switching mechanism) that enables the intermediate transfer rollers 64 to move so as to make contact with, and separate from, the photoreceptor drums 3 .
- the movement mechanism 20 provided in the intermediate transfer belt unit 6 will be described in detail later.
- the intermediate transfer belt 61 is provided so as to make contact with each of the photoreceptor drums 3 . Further, the toner images of each color formed on the photoreceptor drums 3 are successively superimposed and transferred onto the intermediate transfer belt 61 . As a result, a color toner image (multicolor toner image) is formed on the intermediate transfer belt 61 .
- the intermediate transfer belt 61 is formed having an endless shape using a film having a thickness of, for example, approximately 100 ⁇ m to 150 ⁇ m.
- the transfer of the toner images from the photoreceptor drums 3 to the intermediate transfer belt 61 is performed by the intermediate transfer rollers 64 which are in contact with the rear side of the intermediate transfer belt 61 .
- a high-voltage transfer bias (a high voltage having the opposite polarity (+) to the charge polarity of the toner ( ⁇ )) for transferring the toner images is applied to the intermediate transfer rollers 64 .
- the intermediate transfer rollers 64 are rollers formed based on a metal (for example, stainless steel) shaft with a diameter of 8 mm to 10 mm, and the surfaces are covered with a conductive elastic material (such as EPDM or urethane foam).
- the conductive elastic material enables a high voltage to be uniformly applied to the intermediate transfer belt 61 .
- the electrostatic latent images visualized on the photoreceptor drums 3 corresponding to each hue are stacked on the intermediate transfer belt 61 , and then transferred onto a paper sheet by a transfer roller 10 disposed in a contact position between the paper sheet and the intermediate transfer belt 61 .
- the intermediate transfer belt 61 and the transfer roller 10 are pressed against each other at a predetermined nip. Further, a voltage is applied to the transfer roller 10 in order to transfer the toner to the paper sheet (a high voltage having the opposite polarity (+) to the charge polarity of the toner ( ⁇ )).
- the toner attached to the intermediate transfer belt 61 as a result of making contact with the photoreceptor drums 3 or the toner remaining on the intermediate transfer belt 61 due to transfer not being performed onto the paper sheet by the transfer roller 10 is removed and collected by the intermediate transfer belt cleaning unit 65 since such toner causes mixing of the toner colors in the subsequent step.
- the intermediate transfer belt cleaning unit 65 includes, for example, a cleaning blade serving as a cleaning member that makes contact with the intermediate transfer belt 61 .
- the surface of the intermediate transfer belt 61 on the opposite side to the surface that makes contact with the cleaning blade is supported by the intermediate transfer belt driven roller 63 .
- the paper feeding cassette 81 is a tray for storing paper sheets to be used in image formation, and is provided on the lower side of the exposure unit 1 of the printer 110 . Furthermore, the manual paper feeding cassette 82 is provided on a side surface of the printer 110 . In the image forming device 100 , paper sheets can also be manually set in the manual paper feeding cassette 82 .
- the printer 110 further includes a paper discharge tray 91 .
- the paper discharge tray 91 accumulates printed paper sheets in a face-down manner.
- the printer 110 is provided with a sheet transport path S for transporting the paper sheets in the paper feeding cassette 81 and the manual paper feeding cassette 82 to the paper discharge tray 91 via the transfer roller 10 and the fusing unit 7 .
- Pickup rollers 11 a and 11 b , a plurality of transport rollers 12 a to 12 d , a registration roller 13 , the transfer roller 10 , the fusing unit 7 , and the like are disposed along the sheet transport path S from the paper feeding cassette 81 or the manual paper feeding cassette 82 to the paper discharge tray 91 .
- the transport rollers 12 a to 12 d are small rollers for assisting the transport of the paper sheets, and are disposed along the sheet transport path S.
- the pickup roller 11 a is disposed in the vicinity of an end of the paper feeding cassette 81 , picks up the paper sheets one by one from the paper feeding cassette 81 , and supplies the paper sheets to the sheet transport path S.
- the pickup roller 11 b is disposed in the vicinity of an end of the manual paper feeding cassette 82 , picks up the paper sheets one by one from the manual paper feeding cassette 82 , and supplies the paper sheets to the sheet transport path S.
- the registration roller 13 temporarily holds a paper sheet being transported in the sheet transport path S.
- the registration roller 13 transports a paper sheet to the transfer roller 10 at a timing when a leading edge of the toner image on the intermediate transfer belt 61 is aligned with the leading edge of the paper sheet.
- the fusing unit 7 includes a heat roller 71 and a pressure roller 72 .
- the heat roller 71 and the pressure roller 72 rotate with a paper sheet held between them.
- the heat roller 71 is set to a predetermined fusing temperature based on a signal from a temperature detector (not shown). Then, the heat roller 71 , together with the pressure roller 72 , thermally compresses the toner onto the paper sheet.
- the fusing unit 7 can melt, mix, and press the multicolor toner image that has been transferred onto the paper sheet, and thermally fuse the toner image onto the paper sheet.
- the fusing unit 7 includes an external heating belt 73 for externally heating the heat roller 71 .
- FIG. 2 is a diagram schematically showing an example of a configuration when all of the intermediate transfer rollers 64 provided in the intermediate transfer belt unit 6 according to the embodiment of the present disclosure are in a separated position (second position).
- FIG. 3 is a diagram schematically showing an example of a configuration when the intermediate transfer rollers 64 provided in the intermediate transfer belt unit 6 according to the embodiment of the present disclosure are in a pressing position (first position) and a retracted position (third position).
- FIG. 4 is a diagram schematically showing an example of a configuration when all of the intermediate transfer rollers 64 provided in the intermediate transfer belt unit 6 according to the embodiment of the present disclosure are in the pressing position (first position).
- FIG. 5 is a diagram schematically showing an example of a configuration when all of the intermediate transfer rollers 64 provided in the intermediate transfer belt unit 6 according to the embodiment of the present disclosure are in the retracted position.
- FIGS. 2 to 5 are diagrams of the intermediate transfer belt unit 6 when viewed from the front side of the image forming device 100 .
- the intermediate transfer belt 61 is stretched between the intermediate transfer belt drive roller 62 and the intermediate transfer belt driven roller 63 , and forms a predetermined loop-shaped movement path.
- the photoreceptor drum 3 a , the photoreceptor drum 3 b , the photoreceptor drum 3 c , and the photoreceptor drum 3 d are disposed on the outer peripheral surface side of the intermediate transfer belt 61 in this order from the downstream side of the movement direction A of the intermediate transfer belt 61 .
- the first intermediate transfer roller 64 a to fourth intermediate transfer roller 64 d are disposed in positions facing the photoreceptor drums 3 a to 3 d with the intermediate transfer belt 61 held therebetween.
- the intermediate transfer belt 61 is disposed between the photoreceptor drums 3 and the intermediate transfer rollers 64 disposed above the photoreceptor drums 3 .
- the intermediate transfer rollers 64 are capable of moving due to the movement mechanism 20 so as to make contact with, and separate from, the respective opposing photoreceptor drums 3 . Further, the movement mechanism 20 is configured so as to be capable of switching, according to the rotation angle of cams 23 , the positions of the intermediate transfer rollers 64 to one of the pressing position (first position), in which the intermediate transfer belt 61 is pressed against the photoreceptor drums 3 , the separated position (second position) which is separated from the photoreceptor drums 3 , and the retracted position (third position), which is a position that is separated from the photoreceptor drums 3 but having a smaller separation distance from the photoreceptor drums 3 than the separated position.
- the pressing position first position
- second position which is separated from the photoreceptor drums 3
- third position which is a position that is separated from the photoreceptor drums 3 but having a smaller separation distance from the photoreceptor drums 3 than the separated position.
- the separated position is the position of the intermediate transfer rollers 64 when the intermediate transfer belt unit 6 is detached from the image forming device 100 .
- the intermediate transfer rollers 64 are in a position that is, for example, 5 mm away from the photoreceptor drums 3 .
- the pressing position is the position of the intermediate transfer rollers 64 when the toner image formed on the photoreceptor drums 3 is transferred to the intermediate transfer belt when printing is executed, and is a position in which the intermediate transfer rollers 64 press the photoreceptor drums 3 via the intermediate transfer belt 61 .
- each of the first intermediate transfer roller 64 a to fourth intermediate transfer roller 64 d moves to a position that presses the corresponding photoreceptor drum 3 a to photoreceptor drum 3 d .
- the retracted position is the position of the intermediate transfer rollers 64 when the image forming device 100 in print standby.
- the intermediate transfer rollers 64 are in a position that is, for example, in a near position that is 1 mm to 2 mm away from the photoreceptor drums 3 .
- print standby is a state where the image forming device 100 is waiting for a print execution instruction.
- each of the first intermediate transfer roller 64 a to fourth intermediate transfer roller 64 d are in a position that is sufficiently separated from the photoreceptor drum 3 a to photoreceptor drum 3 d .
- the intermediate transfer belt 61 is also in a position that is separated from each of the photoreceptor drum 3 a to photoreceptor drum 3 d.
- the first intermediate transfer roller 64 a corresponding to K is disposed in the pressing position and causes the intermediate transfer belt 61 to make pressing contact with the photoreceptor drum 3 a .
- the second intermediate transfer roller 64 b to fourth intermediate transfer roller 64 d for colors corresponding to each of Y, M, and C are each disposed in the retracted position, which causes the intermediate transfer belt 61 to be separated from each of the photoreceptor drum 3 b to photoreceptor drum 3 d.
- each of the first intermediate transfer roller 64 a to fourth intermediate transfer roller 64 d are disposed in the pressing position, which causes the intermediate transfer belt 61 to make pressing contact with each of the photoreceptor drum 3 a to photoreceptor drum 3 d.
- each of the first intermediate transfer roller 64 a to fourth intermediate transfer roller 64 d are in a position that is separated from, but close to, each of the photoreceptor drum 3 a to the photoreceptor drum 3 d.
- the movement mechanism 20 When the movement mechanism 20 sets the position of the intermediate transfer rollers 64 to the pressing position, the movement mechanism 20 moves the intermediate transfer rollers 64 that are in a state of being held in the retracted position to the pressing position. In other words, the movement mechanism 20 switches the intermediate transfer rollers 64 from a state of being held the retracted position to the pressing position. In this way, when the intermediate transfer rollers 64 are moved to the pressing position, the movement distance of the intermediate transfer rollers 64 can be reduced by controlling the intermediate transfer rollers 64 so as to move from the retracted position. Therefore, the impact noise generated when the photoreceptor drums 3 are pressed by the intermediate transfer rollers 64 can be suppressed.
- the movement of the first intermediate transfer roller 64 a to fourth intermediate transfer roller 64 d is performed by the movement mechanism 20 .
- the configuration of the movement mechanism 20 will be described below.
- the movement mechanism 20 includes first link members 21 , second link members 22 , cams 23 , and a first swing member 24 a to fourth swing member 24 d.
- the first link members 21 are members that are joined to the first swing member 24 a provided with the first intermediate transfer roller 64 a on a leading edge.
- the second link members 22 are members that are joined to the second swing member 24 b to fourth swing member 24 d each provided with the second intermediate transfer roller 64 b to fourth intermediate transfer roller 64 d on a leading edge.
- the first link member 21 and the second link member 22 are disposed so as to extend on the same straight line along the movement direction A of the intermediate transfer belt 61 .
- the first link member 21 and the second link member 22 are provided so as to be capable of moving within a predetermined range along the movement direction A.
- the cam 23 are disposed between the first link member 21 and the second link member 22 .
- the cams 23 are a flat cam having an asymmetric outline (outer peripheral shape). As shown in FIG. 6 , the cams 23 include a first cam 233 that switches the position of the first intermediate transfer roller 64 a , and a second cam 234 that switches the position of each of the second intermediate transfer roller 64 b to fourth intermediate transfer roller 64 d .
- FIG. 6 is a plan view of the intermediate transfer belt unit 6 shown in FIG. 2 . The distance from the center of each of the first cam 233 and the second cam 234 to the outer periphery is not constant, and the outer peripheral shapes of the first cam 233 and the second cam 234 are different. The detailed configuration of the cams 23 will be described later.
- the first link members 21 , the second link members 22 , and the cams 23 are disposed are respectively disposed on the front side and the rear side of the image forming device 100 between the intermediate transfer belt drive roller 62 and the intermediate transfer belt driven roller 63 .
- the first intermediate transfer roller 64 a is supported via the first swing member 24 a between the first link member 21 disposed on the front side and the first link member 21 disposed on the rear side.
- the second intermediate transfer roller 64 b to fourth intermediate transfer roller 64 d are supported via each of the second swing member 24 b to fourth swing member 24 d between the second link member 22 disposed on the front side and the second link member 22 disposed on the rear side.
- the cam 23 on the front side and the cam 23 on the rear side are fixed to a single cam shaft 231 , and rotate in the same phase to each other around the cam shaft 231 .
- the cam shaft 231 is rotated by power transmitted from a drive source 232 .
- a drive source 232 For example, a stepping motor is used as the drive source 232 .
- the intermediate transfer belt unit 6 is configured so that the rotation angle of the cams 23 can be grasped from the rotation speed and rotation time of the cams 23 .
- the first link members 21 making pressing contact with the first cams 233 approach and separate from the cam shaft 231 according to the outer peripheral shape of the first cams 233 .
- the first link members 21 move along the movement direction A according to the outer peripheral shape of the first cams 233 .
- FIGS. 7 and 8 are schematic diagrams showing an example of the main components of the first swing member 24 a included in the intermediate transfer belt unit 6 according to the embodiment of the present disclosure. Note that the first swing member 24 a , and the second swing member 24 b to fourth swing member 24 d are installed left-right symmetrically in FIG. 4 .
- the first swing member 24 a has a shape which is bent in a letter-L shape.
- a first end 241 a which is one end of the first swing member 24 a , is rotatably supported by a frame (not shown) of the intermediate transfer belt unit 6 in a position further on the photoreceptor drum 3 a side than the first link member 21 .
- a second end 242 a which is another end of the first swing member 24 a , is rotatably supported by the first intermediate transfer roller 64 a .
- the first swing member 24 a is biased in a direction in which the first intermediate transfer roller 64 a separates from the photoreceptor drum 3 a , or in other words, toward the upper side, by an elastic member (not shown).
- the first link member 21 is provided with a slit 25 , which is in a position facing the photoreceptor drum 3 a , and extends in a direction that is orthogonal to the movement direction A in a side view.
- the first swing member 24 a has, on the bent portion, a projection 243 a that protrudes in the rotation axis direction of the first intermediate transfer roller 64 a .
- the projection 243 a is capable of moving inside the slit 25 of the first link member 21 along the longitudinal direction of the slit 25 .
- the first intermediate transfer roller 64 a provided on the another end of the first swing member 24 a is, as shown in FIG. 7 , lifted upward with the first swing member 24 a by the biasing force from the elastic member.
- the projection 234 a is positioned at the upper end of the slit 25 , or in other words, at the end on the side that is away from the photoreceptor drum 3 a .
- the intermediate transfer belt 61 is also in a position separated from the photoreceptor drum 3 a.
- the intermediate transfer belt 61 is capable of making pressing contact with the photoreceptor drum 3 a.
- each of the second intermediate transfer roller 64 b to fourth intermediate transfer roller 64 d move to the separated position.
- each of the second intermediate transfer roller 64 b to fourth intermediate transfer roller 64 d are lowered and move to the pressing position.
- the intermediate transfer belt 61 is capable of making pressing contact with the photoreceptor drums 3 b to 3 d.
- FIG. 9 is a diagram showing an example of the configuration of the cam 23 included in the intermediate transfer belt unit 6 according to the embodiment of the present disclosure.
- FIG. 10 is a diagram showing an example of the first cam 233 of the cam 23 shown in FIG. 9 .
- FIG. 11 is a diagram showing an example of the second cam 234 of the cam 23 shown in FIG. 9 .
- the first cam 233 and the second cam 234 are fixed to the cam shaft 231 in positions that are offset in the front-rear direction of the intermediate transfer belt unit 6 , and rotate around the cam shaft 231 .
- the first link member 21 makes contact with the outer periphery of the first cam 233 .
- the second link member 22 makes contact with the outer periphery of the second cam 234 .
- the first link member 21 is disposed so as to make contact with a peripheral edge that minimizes the distance from the center of the first cam 233 (cam shaft 231 ) to the outer periphery. Furthermore, when the first intermediate transfer roller 64 a is in the pressing position, as shown in FIG. 10 , the first link member 21 is disposed so as to make contact with a peripheral edge that maximizes the distance from the center of the first cam 233 (cam shaft 231 ) to the outer periphery. Moreover, when the first intermediate transfer roller 64 a is in the retracted position, as shown in FIG.
- the first link member 21 is disposed so as to make contact with a peripheral edge such that the distance from the center of the first cam 233 to the outer periphery is between the distance when the first intermediate transfer roller 64 a is in the separated position and the distance when the first intermediate transfer roller 64 a is in the pressing position.
- the second link member 22 when each of the second intermediate transfer roller 64 b to fourth intermediate transfer roller 64 d are in the separated position, the second link member 22 is disposed so as to make contact with a peripheral edge that minimizes the distance from the center of the second cam 234 (cam shaft 231 ) to the outer periphery. Also, when each of the second intermediate transfer roller 64 b to fourth intermediate transfer roller 64 d are in the pressing position, as shown in FIG. 11 , the second link member 22 is disposed so as to make contact with a peripheral edge that maximizes the distance from the center of the second cam 234 (cam shaft 231 ) to the outer periphery.
- the second link member 22 is disposed so as to make contact with a peripheral edge such that the distance from the center of the second cam 234 to the outer periphery is between the distance when each of the second intermediate transfer roller 64 b to fourth intermediate transfer roller 64 d are in the separated position and the distance when the second intermediate transfer roller 64 b to fourth intermediate transfer roller 64 d are in the pressing position.
- the positions of the first cam 233 and the second cam 234 when the first intermediate transfer roller 64 a is in the separated position, and each of the second intermediate transfer roller 64 b to fourth intermediate transfer roller 64 d are in the separated position is assumed to be the initial position. From the initial position, when the first cam 233 and the second cam 234 are rotated clockwise 90 degrees at a time, the position of each of the first intermediate transfer roller 64 a to fourth intermediate transfer roller 64 d and the state of the image forming device 100 have the relationship shown in the table in FIG. 12 .
- FIG. 12 is a table showing a correspondence relationship between the rotation angle of the cam 23 included in the intermediate transfer belt unit 6 according to the embodiment of the present disclosure, the operation state of the image forming device 100 , the position of the first intermediate transfer roller 64 a , and the position of the second intermediate transfer roller 64 b to fourth intermediate transfer roller 64 d .
- the rotation angle of the cam 23 here is the rotation angle of the first cam 233 and the second cam 234 .
- the operation state of the image forming device 100 is monochrome printing.
- the operation state of the image forming device 100 is color printing.
- the intermediate transfer belt unit 6 is capable of switching the positions of the first intermediate transfer roller 64 a to fourth intermediate transfer roller 64 d between the separated position, the retracted position, and the pressing position by changing the rotation angle of the cam 23 according to the operation state of the image forming device 100 .
- the image forming device 100 when the image forming device 100 is in print standby, it is possible to position the first intermediate transfer roller 64 a to fourth intermediate transfer roller 64 d in the retracted position.
- FIG. 13 is a diagram showing an example of a cam 123 included in the intermediate transfer belt unit 6 according to the modification of the embodiment of the present disclosure.
- FIG. 14 is a table showing a correspondence relationship between the rotation angle of the cam 123 included in the intermediate transfer belt unit 6 according to the modification of the embodiment of the present disclosure, the operation state of the image forming device 100 , the position of the first intermediate transfer roller 64 a , and the position of the second intermediate transfer roller 64 b to fourth intermediate transfer roller 64 d.
- the cam 23 provided in the intermediate transfer belt unit 6 according to the embodiment of the present disclosure is constituted by two flat cams, namely the first cam 233 and the second cam 234 as described above.
- the intermediate transfer belt unit 6 according to the modification of the embodiment of the present disclosure differs in that it includes a cam 123 constituted by a single flat cam instead of the cam 23 .
- the intermediate transfer belt unit 6 according to the modification of the embodiment of the present disclosure has the same configuration as the intermediate transfer belt unit 6 according to the embodiment except in that the cam 123 is provided instead of the cam 23 . Therefore, the same members are denoted by the same reference numerals, and the descriptions will be omitted.
- the outer periphery of the cam 123 includes a first peripheral edge 123 a , which is a right half outer edge, and a second peripheral edge 123 b , which is the left half outer edge with respect to a straight line that vertically intersects the cam shaft 231 in the up-down direction.
- the distance between the first link member 21 and the cam shaft 231 changes according to the shape of the first peripheral edge 123 a as the cam 123 rotates. In this way, the position of the first intermediate transfer roller 64 a can be switched according to the change in the distance between the first link member 21 and the cam shaft 231 .
- the first intermediate transfer roller 64 a when the distance between the cam shaft 231 and the contact position between first link member 21 and the first peripheral edge 123 a is a smallest first distance, the first intermediate transfer roller 64 a is in the separated position. When the distance between the cam shaft 231 and the contact position between first link member 21 and the first peripheral edge 123 a is a largest second distance, the first intermediate transfer roller 64 a is in the pressing position. Furthermore, when the distance between the cam shaft 231 and the contact position between first link member 21 and the first peripheral edge 123 a is longer than the first distance mentioned above, but shorter than the second distance, the first intermediate transfer roller 64 a is in the retracted position.
- the distance between the second link member 22 and the cam shaft 231 changes according to the shape of the second peripheral edge 123 b as the cam 123 rotates.
- the positions of the second intermediate transfer roller 64 b to fourth intermediate transfer roller 64 d can be switched according to the change in the distance between the second link member 22 and the cam shaft 231 .
- the second intermediate transfer roller 64 b to fourth intermediate transfer roller 64 d are in the separated position.
- the second intermediate transfer roller 64 b to fourth intermediate transfer roller 64 d are in the pressing position.
- the second intermediate transfer roller 64 b to fourth intermediate transfer roller 64 d are in the retracted position.
- a state where the first intermediate transfer roller 64 a and each of the second intermediate transfer roller 64 b to fourth intermediate transfer roller 64 d are in the separated position is assumed to be the initial position.
- the cam 123 rotates clockwise from the initial position as shown in FIG. 14 , the positions of each of the first intermediate transfer roller 64 a to fourth intermediate transfer roller 64 d are switched.
- the operation state of the image forming device 100 is detachment of the intermediate transfer belt unit 6 .
- the operation state of the image forming device 100 is monochrome printing.
- the operation state of the image forming device 100 is color printing.
- the intermediate transfer belt unit 6 has a configuration in which the position of the first intermediate transfer roller 64 a is switched by the position of the first peripheral edge 123 a according to the rotation angle of the cam 123 , and the positions of the second intermediate transfer roller 64 b to fourth intermediate transfer roller 64 d are switched by the position of the second peripheral edge 123 b .
- the rotation direction of the cam 123 is configured to be reversed when rotated by 135 degrees from the initial position.
- the intermediate transfer belt unit 6 according to the modification of the embodiment includes the cam 123 , the number of components constituting the cam can be reduced compared to the intermediate transfer belt unit 6 according to the embodiment.
- the intermediate transfer belt unit 6 according to the embodiment has a larger rotation angle for switching the position of the intermediate transfer rollers 64 than the intermediate transfer belt unit 6 according to the modification of the embodiment, and the rotation angle is also a single direction. As a result, a switching control of the positions of the intermediate transfer rollers 64 can be more easily performed in the intermediate transfer belt unit 6 according to the embodiment than the intermediate transfer belt unit 6 according to the modification of the embodiment.
- the image forming device 100 includes an operation button (not shown), and a configuration is possible in which a detachment instruction of the intermediate transfer belt unit 6 is received by the operation button.
- the movement mechanism 20 moves the positions of the first intermediate transfer roller 64 a to fourth intermediate transfer roller 64 d to the separated position only when a detachment instruction is received.
- a configuration is possible in which the movement mechanism 20 switches the positions of the first intermediate transfer roller 64 a to fourth intermediate transfer roller 64 d to either the retracted position or the pressing position according to the operation state of the image forming device 100 .
- the movement mechanism 20 controls the positions of the first intermediate transfer roller 64 a to fourth intermediate transfer roller 64 d so as to switch to either the retracted position or the pressing position. Therefore, the switching control of the positions becomes easier.
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Abstract
An image forming device includes one or more image carriers on which a toner image is formed; a transfer belt that transfers a toner image formed on the image carrier; a presser that presses the transfer belt against the image carrier to transfer the toner image onto the transfer belt; and a switching mechanism that switches a position of the presser according to a rotation angle of a cam. The switching mechanism switches a position of the presser to one of a first position that presses the transfer belt against the image carrier, a second position that is separated from the image carrier, and a third position that is a position separated from the image carrier and having a smaller separation distance from the image carrier than the second position.
Description
- The present application claims priority from Japanese Application JP2022-175905, filed on Nov. 2, 2022, the content of which is hereby incorporated by reference into this application.
- The present disclosure relates to an image forming device.
- As a conventional technique, proposed is an image forming device including a transfer device that transfers a toner image from an image carrier to a paper sheet via an intermediate transfer belt.
- In the image forming device disclosed in the conventional technique, the transfer device is provided with a transfer roller that can be displaced in a direction that makes contact with, and separates from, the image carrier.
- However, when a presser (transfer roller) in a position that is separated from the image carrier moves to a position that presses the image carrier, and then presses the image carrier, a large impact sound is generated between the presser and the image carrier.
- An object of the present disclosure is to provide an image forming device that enables an impact sound generated when an image carrier is pressed by a presser to be suppressed.
- An image forming device according to an aspect of the present disclosure includes: one or more image carriers on which a toner image is formed; a transfer belt that transfers a toner image formed on the image carrier; a presser that presses the transfer belt against the image carrier to transfer the toner image onto the transfer belt; and a switching mechanism that switches a position of the presser according to a rotation angle of a cam; wherein the switching mechanism switches a position of the presser to one of a first position that presses the transfer belt against the image carrier, a second position that is separated from the image carrier, and a third position that is a position separated from the image carrier and having a smaller separation distance from the image carrier than the second position.
- According to an aspect of the present disclosure, an image forming device is capable of suppressing an impact sound generated when an image carrier is pressed by a presser.
-
FIG. 1 is a schematic diagram showing an example of an internal structure of an image forming device according to an embodiment of the present disclosure. -
FIG. 2 is a diagram schematically showing an example of a configuration when all of the intermediate transfer rollers provided in an intermediate transfer belt unit according to the embodiment of the present disclosure are in a separated position. -
FIG. 3 is a diagram schematically showing an example of a configuration when the intermediate transfer rollers provided in the intermediate transfer belt unit according to the embodiment of the present disclosure are in a pressing position and a retracted position. -
FIG. 4 is a diagram schematically showing an example of a configuration when all of the intermediate transfer rollers provided in the intermediate transfer belt unit according to the embodiment of the present disclosure are in the pressing position. -
FIG. 5 is a diagram schematically showing an example of a configuration when all of the intermediate transfer rollers provided in the intermediate transfer belt unit according to the embodiment of the present disclosure are in the retracted position. -
FIG. 6 is a plan view of the intermediate transfer belt unit shown inFIG. 2 . -
FIG. 7 is a schematic diagram showing an example of the main components of a first swing member included in the intermediate transfer belt unit according to the embodiment of the present disclosure. -
FIG. 8 is a schematic diagram showing an example of the main components of a first swing member included in the intermediate transfer belt unit according to the embodiment of the present disclosure. -
FIG. 9 is a diagram showing an example of the configuration of a cam included in the intermediate transfer belt unit according to the embodiment of the present disclosure. -
FIG. 10 is a diagram showing an example of a first cam of the cam shown inFIG. 9 . -
FIG. 11 is a diagram showing an example of a second cam of the cam shown inFIG. 9 . -
FIG. 12 is a table showing a correspondence relationship between the rotation angle of the cam included in the intermediate transfer belt unit according to the embodiment of the present disclosure, the operation state of the image forming device, the position of a first intermediate transfer roller, and the position of a second intermediate transfer roller to fourth intermediate transfer roller. -
FIG. 13 is a diagram showing an example of a cam included in an intermediate transfer belt unit according to a modification of the embodiment of the present disclosure. -
FIG. 14 is a table showing a correspondence relationship between the rotation angle of the cam included in the intermediate transfer belt unit according to the modification of the embodiment of the present disclosure, the operation state of the image forming device, the position of a first intermediate transfer roller, and the position of a second intermediate transfer roller to fourth intermediate transfer roller. - Hereinafter, an embodiment and modification of the present disclosure will be described with reference to the accompanying drawings. The same reference numerals are given below to the same or equivalent components throughout all the drawings, and duplicate descriptions are omitted. The embodiment and modification described below are merely examples of the present disclosure, and the present disclosure is not limited to the embodiment and modification. In addition to the embodiment and modification, various changes may be made according to the design and the like without departing from the technical concept of the present disclosure.
- An
image forming device 100 according to the embodiment of the present disclosure will be described with reference toFIG. 1 .FIG. 1 is a schematic diagram showing an example of an internal structure of animage forming device 100 according to the embodiment of the present disclosure.FIG. 1 is a diagram of the internal structure of theimage forming device 100 when viewed from the front side. Note that, in theimage forming device 100, of the horizontal directions when viewed from the front side, the left side is defined as the left direction, and the right side is defined as the right direction. Furthermore, of the depth directions when viewed from the front side, the front side (near side) of theimage forming device 100 is defined as the front direction, and the rear side (far side) is defined as the rear direction. Moreover, in theimage forming device 100, the bottom side is defined as the downward direction, and the opposite side is defined as the upward direction. - The
image forming device 100 is a laser color printer that forms multicolor and monochrome images on a paper sheet on which an image is formed. Theimage forming device 100 prints an image on a paper sheet based on image data read from a document by animage reading device 90, or image data received from an external source. Note that, although a laser color printer is described as an example of theimage forming device 100 in the present embodiment, the present disclosure is not limited to this. - As shown in
FIG. 1 , theimage forming device 100 includes aprinter 110, animage reading device 90, a document table 92, and an automaticdocument processing device 120. Theprinter 110 includes an exposure unit 1, developers 2,photoreceptor drums 3 a to 3 d (image carriers), cleaner units 4,chargers 5, an intermediatetransfer belt unit 6, afusing unit 7, apaper feeding cassette 81, and a manualpaper feeding cassette 82. Thephotoreceptor drums 3 a to 3 d are simply referred to as the photoreceptor drums 3 when there is no need for the description to distinguish between them. - The upper part of the
printer 110 is provided with theimage reading device 90 and the document table 92, which is made of transparent glass. Furthermore, the automaticdocument processing device 120 is installed on the upper side of the document table 92. - The automatic
document processing device 120 automatically transports a document onto the document table 92. Moreover, the automaticdocument processing device 120 is configured so as to be rotatable in the direction of arrow R. Further, a document can be placed on the document table 92 by opening the top of the document table 92. - The
image reading device 90 reads image data from a document transported or placed on the document table 92. Theprinter 110 prints an image on a paper sheet based on the image data read by theimage reading device 90. - The image data handled by the
image forming device 100 corresponds to a color image that uses each of cyan (C), magenta (M), yellow (Y), and black (K) colors. Accordingly, the developers 2, the photoreceptor drums 3, the cleaner units 4, and thechargers 5 are each provided so as to form four types of latent images corresponding to the respective colors. - The
chargers 5 uniformly charge the surfaces of the photoreceptor drums 3 to a predetermined potential. Thechargers 5 may be charger type, contact type, or brush type chargers or the like. - The exposure unit 1 is configured as a laser scanning unit (LSU) provided with a laser emitter, a reflecting mirror, and the like. The exposure unit 1 includes polygon mirrors for performing scanning with a laser beam, and optical components, such as lenses or mirrors, for guiding the laser beam reflected by the polygon mirrors to the photoreceptor drums 3. The exposure unit 1 exposes the charged photoreceptor drums 3 according to the image data to form electrostatic latent images corresponding to the image data on the surfaces of the photoreceptor drums 3.
- The developers 2 visualize the electrostatic latent images formed on the photoreceptor drums 3 using toner. The toner images are formed on the photoreceptor drums 3 as a result of being visualized with toner. The developers 2 include
developer tanks 2 a, and the toner is accommodated in thedeveloper tanks 2 a. The developers 2 are configured to supply the toner accommodated in thedeveloper tanks 2 a to the photoreceptor drums 3. Furthermore, thedeveloper tanks 2 a are connected totoner cartridges 8 that accommodate the toner via toner supply pipes (not shown). Thetoner cartridges 8 are provided for each of the four toner colors. - The cleaner units 4 remove and collect the residual toner remaining on the surfaces of the photoreceptor drums 3 after development and image transfer.
- The intermediate
transfer belt unit 6 is disposed above the photoreceptor drums 3. The intermediatetransfer belt unit 6 includes an intermediate transfer belt 61 (transfer belt), an intermediate transferbelt drive roller 62, an intermediate transfer belt drivenroller 63, a firstintermediate transfer roller 64 a to fourthintermediate transfer roller 64 d (pressers), and an intermediate transferbelt cleaning unit 65. The firstintermediate transfer roller 64 a to fourthintermediate transfer roller 64 d are provided corresponding to the respective colors of K, Y, M, and C. Note that the firstintermediate transfer roller 64 a to fourthintermediate transfer roller 64 d are simply referred to as the intermediate transfer rollers 64 when there is no need for the description to distinguish between them. - The intermediate transfer
belt drive roller 62, the intermediate transfer belt drivenroller 63, and the firstintermediate transfer roller 64 a to fourthintermediate transfer roller 64 d each stretch and rotationally drive theintermediate transfer belt 61. - The intermediate transfer rollers 64 apply a transfer bias for transferring the toner images of the photoreceptor drums 3 onto the
intermediate transfer belt 61, and also press the photoreceptor drums 3. The position in which the intermediate transfer rollers 64 press the photoreceptor drums 3 via theintermediate transfer belt 61 is referred to as the pressing position (first position). - Furthermore, although not illustrated in
FIG. 1 , in theimage forming device 100, the intermediatetransfer belt unit 6 further includes a movement mechanism 20 (switching mechanism) that enables the intermediate transfer rollers 64 to move so as to make contact with, and separate from, the photoreceptor drums 3. Themovement mechanism 20 provided in the intermediatetransfer belt unit 6 will be described in detail later. - The
intermediate transfer belt 61 is provided so as to make contact with each of the photoreceptor drums 3. Further, the toner images of each color formed on the photoreceptor drums 3 are successively superimposed and transferred onto theintermediate transfer belt 61. As a result, a color toner image (multicolor toner image) is formed on theintermediate transfer belt 61. Theintermediate transfer belt 61 is formed having an endless shape using a film having a thickness of, for example, approximately 100 μm to 150 μm. - The transfer of the toner images from the photoreceptor drums 3 to the
intermediate transfer belt 61 is performed by the intermediate transfer rollers 64 which are in contact with the rear side of theintermediate transfer belt 61. A high-voltage transfer bias (a high voltage having the opposite polarity (+) to the charge polarity of the toner (−)) for transferring the toner images is applied to the intermediate transfer rollers 64. The intermediate transfer rollers 64 are rollers formed based on a metal (for example, stainless steel) shaft with a diameter of 8 mm to 10 mm, and the surfaces are covered with a conductive elastic material (such as EPDM or urethane foam). The conductive elastic material enables a high voltage to be uniformly applied to theintermediate transfer belt 61. - The electrostatic latent images visualized on the photoreceptor drums 3 corresponding to each hue are stacked on the
intermediate transfer belt 61, and then transferred onto a paper sheet by a transfer roller 10 disposed in a contact position between the paper sheet and theintermediate transfer belt 61. - At this time, the
intermediate transfer belt 61 and the transfer roller 10 are pressed against each other at a predetermined nip. Further, a voltage is applied to the transfer roller 10 in order to transfer the toner to the paper sheet (a high voltage having the opposite polarity (+) to the charge polarity of the toner (−)). - Moreover, as described above, the toner attached to the
intermediate transfer belt 61 as a result of making contact with the photoreceptor drums 3 or the toner remaining on theintermediate transfer belt 61 due to transfer not being performed onto the paper sheet by the transfer roller 10, is removed and collected by the intermediate transferbelt cleaning unit 65 since such toner causes mixing of the toner colors in the subsequent step. - The intermediate transfer
belt cleaning unit 65 includes, for example, a cleaning blade serving as a cleaning member that makes contact with theintermediate transfer belt 61. The surface of theintermediate transfer belt 61 on the opposite side to the surface that makes contact with the cleaning blade is supported by the intermediate transfer belt drivenroller 63. - The
paper feeding cassette 81 is a tray for storing paper sheets to be used in image formation, and is provided on the lower side of the exposure unit 1 of theprinter 110. Furthermore, the manualpaper feeding cassette 82 is provided on a side surface of theprinter 110. In theimage forming device 100, paper sheets can also be manually set in the manualpaper feeding cassette 82. - The
printer 110 further includes apaper discharge tray 91. Thepaper discharge tray 91 accumulates printed paper sheets in a face-down manner. - Furthermore, the
printer 110 is provided with a sheet transport path S for transporting the paper sheets in thepaper feeding cassette 81 and the manualpaper feeding cassette 82 to thepaper discharge tray 91 via the transfer roller 10 and thefusing unit 7.Pickup rollers transport rollers 12 a to 12 d, aregistration roller 13, the transfer roller 10, thefusing unit 7, and the like are disposed along the sheet transport path S from thepaper feeding cassette 81 or the manualpaper feeding cassette 82 to thepaper discharge tray 91. - The
transport rollers 12 a to 12 d are small rollers for assisting the transport of the paper sheets, and are disposed along the sheet transport path S. Thepickup roller 11 a is disposed in the vicinity of an end of thepaper feeding cassette 81, picks up the paper sheets one by one from thepaper feeding cassette 81, and supplies the paper sheets to the sheet transport path S. Similarly, thepickup roller 11 b is disposed in the vicinity of an end of the manualpaper feeding cassette 82, picks up the paper sheets one by one from the manualpaper feeding cassette 82, and supplies the paper sheets to the sheet transport path S. - The
registration roller 13 temporarily holds a paper sheet being transported in the sheet transport path S. Theregistration roller 13 transports a paper sheet to the transfer roller 10 at a timing when a leading edge of the toner image on theintermediate transfer belt 61 is aligned with the leading edge of the paper sheet. - The
fusing unit 7 includes aheat roller 71 and apressure roller 72. Theheat roller 71 and thepressure roller 72 rotate with a paper sheet held between them. Furthermore, theheat roller 71 is set to a predetermined fusing temperature based on a signal from a temperature detector (not shown). Then, theheat roller 71, together with thepressure roller 72, thermally compresses the toner onto the paper sheet. As a result, thefusing unit 7 can melt, mix, and press the multicolor toner image that has been transferred onto the paper sheet, and thermally fuse the toner image onto the paper sheet. Thefusing unit 7 includes anexternal heating belt 73 for externally heating theheat roller 71. - Movement Mechanism
- Next, a configuration of the
movement mechanism 20 provided in the intermediatetransfer belt unit 6 will be described with reference toFIGS. 2 to 5 .FIG. 2 is a diagram schematically showing an example of a configuration when all of the intermediate transfer rollers 64 provided in the intermediatetransfer belt unit 6 according to the embodiment of the present disclosure are in a separated position (second position).FIG. 3 is a diagram schematically showing an example of a configuration when the intermediate transfer rollers 64 provided in the intermediatetransfer belt unit 6 according to the embodiment of the present disclosure are in a pressing position (first position) and a retracted position (third position).FIG. 4 is a diagram schematically showing an example of a configuration when all of the intermediate transfer rollers 64 provided in the intermediatetransfer belt unit 6 according to the embodiment of the present disclosure are in the pressing position (first position).FIG. 5 is a diagram schematically showing an example of a configuration when all of the intermediate transfer rollers 64 provided in the intermediatetransfer belt unit 6 according to the embodiment of the present disclosure are in the retracted position.FIGS. 2 to 5 are diagrams of the intermediatetransfer belt unit 6 when viewed from the front side of theimage forming device 100. - As shown in
FIGS. 2 to 5 , theintermediate transfer belt 61 is stretched between the intermediate transferbelt drive roller 62 and the intermediate transfer belt drivenroller 63, and forms a predetermined loop-shaped movement path. Thephotoreceptor drum 3 a, thephotoreceptor drum 3 b, thephotoreceptor drum 3 c, and thephotoreceptor drum 3 d are disposed on the outer peripheral surface side of theintermediate transfer belt 61 in this order from the downstream side of the movement direction A of theintermediate transfer belt 61. The firstintermediate transfer roller 64 a to fourthintermediate transfer roller 64 d are disposed in positions facing the photoreceptor drums 3 a to 3 d with theintermediate transfer belt 61 held therebetween. In the present embodiment, theintermediate transfer belt 61 is disposed between the photoreceptor drums 3 and the intermediate transfer rollers 64 disposed above the photoreceptor drums 3. - The intermediate transfer rollers 64 are capable of moving due to the
movement mechanism 20 so as to make contact with, and separate from, the respective opposing photoreceptor drums 3. Further, themovement mechanism 20 is configured so as to be capable of switching, according to the rotation angle ofcams 23, the positions of the intermediate transfer rollers 64 to one of the pressing position (first position), in which theintermediate transfer belt 61 is pressed against the photoreceptor drums 3, the separated position (second position) which is separated from the photoreceptor drums 3, and the retracted position (third position), which is a position that is separated from the photoreceptor drums 3 but having a smaller separation distance from the photoreceptor drums 3 than the separated position. - The separated position is the position of the intermediate transfer rollers 64 when the intermediate
transfer belt unit 6 is detached from theimage forming device 100. When in the separated position, the intermediate transfer rollers 64 are in a position that is, for example, 5 mm away from the photoreceptor drums 3. - Furthermore, the pressing position is the position of the intermediate transfer rollers 64 when the toner image formed on the photoreceptor drums 3 is transferred to the intermediate transfer belt when printing is executed, and is a position in which the intermediate transfer rollers 64 press the photoreceptor drums 3 via the
intermediate transfer belt 61. When color printing is executed, each of the firstintermediate transfer roller 64 a to fourthintermediate transfer roller 64 d moves to a position that presses the correspondingphotoreceptor drum 3 a tophotoreceptor drum 3 d. However, when monochrome printing is performed, only the firstintermediate transfer roller 64 a that presses thephotoreceptor drum 3 a (first image carrier) corresponding to K moves to the pressing position, and the secondintermediate transfer roller 64 b to fourthintermediate transfer roller 64 d move to the retracted position. - The retracted position is the position of the intermediate transfer rollers 64 when the
image forming device 100 in print standby. When in the retracted position, the intermediate transfer rollers 64 are in a position that is, for example, in a near position that is 1 mm to 2 mm away from the photoreceptor drums 3. Note that print standby is a state where theimage forming device 100 is waiting for a print execution instruction. - Specifically, in the intermediate
transfer belt unit 6, when the intermediate transfer rollers 64 are in the separated position, for example, as shown inFIG. 2 , each of the firstintermediate transfer roller 64 a to fourthintermediate transfer roller 64 d are in a position that is sufficiently separated from thephotoreceptor drum 3 a tophotoreceptor drum 3 d. At this time, theintermediate transfer belt 61 is also in a position that is separated from each of thephotoreceptor drum 3 a tophotoreceptor drum 3 d. - Furthermore, at the time of monochrome printing, for example, as shown in
FIG. 3 , the firstintermediate transfer roller 64 a corresponding to K is disposed in the pressing position and causes theintermediate transfer belt 61 to make pressing contact with thephotoreceptor drum 3 a. On the other hand, the secondintermediate transfer roller 64 b to fourthintermediate transfer roller 64 d for colors corresponding to each of Y, M, and C, are each disposed in the retracted position, which causes theintermediate transfer belt 61 to be separated from each of thephotoreceptor drum 3 b tophotoreceptor drum 3 d. - Moreover, at the time of color printing, for example, as shown in
FIG. 4 , each of the firstintermediate transfer roller 64 a to fourthintermediate transfer roller 64 d are disposed in the pressing position, which causes theintermediate transfer belt 61 to make pressing contact with each of thephotoreceptor drum 3 a tophotoreceptor drum 3 d. - In addition, during print standby, for example, as shown in
FIG. 5 , each of the firstintermediate transfer roller 64 a to fourthintermediate transfer roller 64 d are in a position that is separated from, but close to, each of thephotoreceptor drum 3 a to thephotoreceptor drum 3 d. - When the
movement mechanism 20 sets the position of the intermediate transfer rollers 64 to the pressing position, themovement mechanism 20 moves the intermediate transfer rollers 64 that are in a state of being held in the retracted position to the pressing position. In other words, themovement mechanism 20 switches the intermediate transfer rollers 64 from a state of being held the retracted position to the pressing position. In this way, when the intermediate transfer rollers 64 are moved to the pressing position, the movement distance of the intermediate transfer rollers 64 can be reduced by controlling the intermediate transfer rollers 64 so as to move from the retracted position. Therefore, the impact noise generated when the photoreceptor drums 3 are pressed by the intermediate transfer rollers 64 can be suppressed. - Further, as described above, the movement of the first
intermediate transfer roller 64 a to fourthintermediate transfer roller 64 d is performed by themovement mechanism 20. The configuration of themovement mechanism 20 will be described below. - The
movement mechanism 20 includesfirst link members 21,second link members 22,cams 23, and afirst swing member 24 a tofourth swing member 24 d. - The
first link members 21 are members that are joined to thefirst swing member 24 a provided with the firstintermediate transfer roller 64 a on a leading edge. Furthermore, thesecond link members 22 are members that are joined to thesecond swing member 24 b tofourth swing member 24 d each provided with the secondintermediate transfer roller 64 b to fourthintermediate transfer roller 64 d on a leading edge. - As shown in
FIG. 2 , when the intermediatetransfer belt unit 6 is viewed from the side, thefirst link member 21 and thesecond link member 22 are disposed so as to extend on the same straight line along the movement direction A of theintermediate transfer belt 61. Thefirst link member 21 and thesecond link member 22 are provided so as to be capable of moving within a predetermined range along the movement direction A. Note that thecam 23 are disposed between thefirst link member 21 and thesecond link member 22. - The
cams 23 are a flat cam having an asymmetric outline (outer peripheral shape). As shown inFIG. 6 , thecams 23 include afirst cam 233 that switches the position of the firstintermediate transfer roller 64 a, and asecond cam 234 that switches the position of each of the secondintermediate transfer roller 64 b to fourthintermediate transfer roller 64 d.FIG. 6 is a plan view of the intermediatetransfer belt unit 6 shown inFIG. 2 . The distance from the center of each of thefirst cam 233 and thesecond cam 234 to the outer periphery is not constant, and the outer peripheral shapes of thefirst cam 233 and thesecond cam 234 are different. The detailed configuration of thecams 23 will be described later. - Furthermore, as shown in
FIG. 6 , thefirst link members 21, thesecond link members 22, and thecams 23 are disposed are respectively disposed on the front side and the rear side of theimage forming device 100 between the intermediate transferbelt drive roller 62 and the intermediate transfer belt drivenroller 63. - The first
intermediate transfer roller 64 a is supported via thefirst swing member 24 a between thefirst link member 21 disposed on the front side and thefirst link member 21 disposed on the rear side. On the other hand, the secondintermediate transfer roller 64 b to fourthintermediate transfer roller 64 d are supported via each of thesecond swing member 24 b tofourth swing member 24 d between thesecond link member 22 disposed on the front side and thesecond link member 22 disposed on the rear side. - The
cam 23 on the front side and thecam 23 on the rear side are fixed to asingle cam shaft 231, and rotate in the same phase to each other around thecam shaft 231. Thecam shaft 231 is rotated by power transmitted from adrive source 232. For example, a stepping motor is used as thedrive source 232. The intermediatetransfer belt unit 6 is configured so that the rotation angle of thecams 23 can be grasped from the rotation speed and rotation time of thecams 23. - Furthermore, as a result of the
first cam 233 of thecams 23 rotating, thefirst link members 21 making pressing contact with thefirst cams 233 approach and separate from thecam shaft 231 according to the outer peripheral shape of thefirst cams 233. In this way, thefirst link members 21 move along the movement direction A according to the outer peripheral shape of thefirst cams 233. - Furthermore, as a result of the
second cam 234 of thecams 23 rotating, thesecond link members 22 making pressing contact with thesecond cams 234 move along the movement direction A according to the outer peripheral shape of thesecond cams 234. - Here, the configuration of the
first swing member 24 a tofourth swing member 24 d will be described in more detail with reference toFIGS. 7 and 8 . Note that thefirst swing member 24 a has the same configuration as thesecond swing member 24 b tofourth swing member 24 d except for a difference in installation direction. Further, for convenience of description, thefirst swing member 24 a will be described as an example.FIGS. 7 and 8 are schematic diagrams showing an example of the main components of thefirst swing member 24 a included in the intermediatetransfer belt unit 6 according to the embodiment of the present disclosure. Note that thefirst swing member 24 a, and thesecond swing member 24 b tofourth swing member 24 d are installed left-right symmetrically inFIG. 4 . - As shown in
FIGS. 7 and 8 , thefirst swing member 24 a has a shape which is bent in a letter-L shape. Afirst end 241 a, which is one end of thefirst swing member 24 a, is rotatably supported by a frame (not shown) of the intermediatetransfer belt unit 6 in a position further on thephotoreceptor drum 3 a side than thefirst link member 21. Asecond end 242 a, which is another end of thefirst swing member 24 a, is rotatably supported by the firstintermediate transfer roller 64 a. Furthermore, thefirst swing member 24 a is biased in a direction in which the firstintermediate transfer roller 64 a separates from thephotoreceptor drum 3 a, or in other words, toward the upper side, by an elastic member (not shown). - Moreover, as shown in
FIGS. 7 and 8 , thefirst link member 21 is provided with aslit 25, which is in a position facing thephotoreceptor drum 3 a, and extends in a direction that is orthogonal to the movement direction A in a side view. - The
first swing member 24 a has, on the bent portion, aprojection 243 a that protrudes in the rotation axis direction of the firstintermediate transfer roller 64 a. Theprojection 243 a is capable of moving inside theslit 25 of thefirst link member 21 along the longitudinal direction of theslit 25. - When the
first link member 21 is in a position close to thecam shaft 231, the firstintermediate transfer roller 64 a provided on the another end of thefirst swing member 24 a is, as shown inFIG. 7 , lifted upward with thefirst swing member 24 a by the biasing force from the elastic member. At this time, the projection 234 a is positioned at the upper end of theslit 25, or in other words, at the end on the side that is away from thephotoreceptor drum 3 a. In this way, when the intermediate transfer rollers 64 are in a position separated from thephotoreceptor drum 3 a, theintermediate transfer belt 61 is also in a position separated from thephotoreceptor drum 3 a. - On the other hand, when the
first link member 21 moves to a position that is more separated than the position near thecam shaft 231, as shown inFIG. 8 , thefirst swing member 24 a is lowered against the biasing force from the elastic member, and the firstintermediate transfer roller 64 a moves to the pressing position. As a result, theintermediate transfer belt 61 is capable of making pressing contact with thephotoreceptor drum 3 a. - Similarly, when the
second link member 22 is in a position near thecam shaft 231, each of the secondintermediate transfer roller 64 b to fourthintermediate transfer roller 64 d move to the separated position. On the other hand, when thesecond link member 22 moves to a position that is more separated than the position near thecam shaft 231, each of the secondintermediate transfer roller 64 b to fourthintermediate transfer roller 64 d are lowered and move to the pressing position. As a result, theintermediate transfer belt 61 is capable of making pressing contact with thephotoreceptor drums 3 b to 3 d. - Next, the
cam 23 will be described in more detail with reference toFIGS. 9 to 11 .FIG. 9 is a diagram showing an example of the configuration of thecam 23 included in the intermediatetransfer belt unit 6 according to the embodiment of the present disclosure.FIG. 10 is a diagram showing an example of thefirst cam 233 of thecam 23 shown inFIG. 9 . Furthermore,FIG. 11 is a diagram showing an example of thesecond cam 234 of thecam 23 shown inFIG. 9 . - As shown in
FIG. 9 , thefirst cam 233 and thesecond cam 234 are fixed to thecam shaft 231 in positions that are offset in the front-rear direction of the intermediatetransfer belt unit 6, and rotate around thecam shaft 231. Thefirst link member 21 makes contact with the outer periphery of thefirst cam 233. Thesecond link member 22 makes contact with the outer periphery of thesecond cam 234. - For example, in the intermediate
transfer belt unit 6, when the firstintermediate transfer roller 64 a is in the separated position, as shown inFIG. 10 , thefirst link member 21 is disposed so as to make contact with a peripheral edge that minimizes the distance from the center of the first cam 233 (cam shaft 231) to the outer periphery. Furthermore, when the firstintermediate transfer roller 64 a is in the pressing position, as shown inFIG. 10 , thefirst link member 21 is disposed so as to make contact with a peripheral edge that maximizes the distance from the center of the first cam 233 (cam shaft 231) to the outer periphery. Moreover, when the firstintermediate transfer roller 64 a is in the retracted position, as shown inFIG. 10 , thefirst link member 21 is disposed so as to make contact with a peripheral edge such that the distance from the center of thefirst cam 233 to the outer periphery is between the distance when the firstintermediate transfer roller 64 a is in the separated position and the distance when the firstintermediate transfer roller 64 a is in the pressing position. - In addition, as shown in
FIG. 11 , when each of the secondintermediate transfer roller 64 b to fourthintermediate transfer roller 64 d are in the separated position, thesecond link member 22 is disposed so as to make contact with a peripheral edge that minimizes the distance from the center of the second cam 234 (cam shaft 231) to the outer periphery. Also, when each of the secondintermediate transfer roller 64 b to fourthintermediate transfer roller 64 d are in the pressing position, as shown inFIG. 11 , thesecond link member 22 is disposed so as to make contact with a peripheral edge that maximizes the distance from the center of the second cam 234 (cam shaft 231) to the outer periphery. Moreover, when each of the secondintermediate transfer roller 64 b to fourthintermediate transfer roller 64 d are in the retracted position, as shown inFIG. 11 , thesecond link member 22 is disposed so as to make contact with a peripheral edge such that the distance from the center of thesecond cam 234 to the outer periphery is between the distance when each of the secondintermediate transfer roller 64 b to fourthintermediate transfer roller 64 d are in the separated position and the distance when the secondintermediate transfer roller 64 b to fourthintermediate transfer roller 64 d are in the pressing position. - For example, the positions of the
first cam 233 and thesecond cam 234 when the firstintermediate transfer roller 64 a is in the separated position, and each of the secondintermediate transfer roller 64 b to fourthintermediate transfer roller 64 d are in the separated position is assumed to be the initial position. From the initial position, when thefirst cam 233 and thesecond cam 234 are rotated clockwise 90 degrees at a time, the position of each of the firstintermediate transfer roller 64 a to fourthintermediate transfer roller 64 d and the state of theimage forming device 100 have the relationship shown in the table inFIG. 12 .FIG. 12 is a table showing a correspondence relationship between the rotation angle of thecam 23 included in the intermediatetransfer belt unit 6 according to the embodiment of the present disclosure, the operation state of theimage forming device 100, the position of the firstintermediate transfer roller 64 a, and the position of the secondintermediate transfer roller 64 b to fourthintermediate transfer roller 64 d. Note that the rotation angle of thecam 23 here is the rotation angle of thefirst cam 233 and thesecond cam 234. - That is, as shown in
FIG. 12 , when thecam 23 is in the initial position, or in other words, when the rotation angle of thecam 23 is 0 degrees, the firstintermediate transfer roller 64 a and each of the secondintermediate transfer roller 64 b to fourthintermediate transfer roller 64 d are positioned in the separated position. At this time, the operation state of theimage forming device 100 is detachment of the intermediatetransfer belt unit 6. - When the
cam 23 rotates 90 degrees from the initial position, the firstintermediate transfer roller 64 a and each of the secondintermediate transfer roller 64 b to fourthintermediate transfer roller 64 d are positioned in the retracted position. At this time, the operation state of theimage forming device 100 is print standby. - When the
cam 23 rotates 180 degrees from the initial position, the firstintermediate transfer roller 64 a is positioned in the pressing position, and each of the secondintermediate transfer roller 64 b to fourthintermediate transfer roller 64 d are positioned in the retracted position. At this time, the operation state of theimage forming device 100 is monochrome printing. - Furthermore, when the
cam 23 rotates 270 degrees from the initial position, the firstintermediate transfer roller 64 a and the secondintermediate transfer roller 64 b to fourthintermediate transfer roller 64 d are positioned in the pressing position. At this time, the operation state of theimage forming device 100 is color printing. - As described above, the intermediate
transfer belt unit 6 is capable of switching the positions of the firstintermediate transfer roller 64 a to fourthintermediate transfer roller 64 d between the separated position, the retracted position, and the pressing position by changing the rotation angle of thecam 23 according to the operation state of theimage forming device 100. In particular, when theimage forming device 100 is in print standby, it is possible to position the firstintermediate transfer roller 64 a to fourthintermediate transfer roller 64 d in the retracted position. As a result, it is possible to suppress the impact noise generated when the operation state of theimage forming device 100 transitions from print standby to monochrome printing or color printing, and the photoreceptor drums 3 a to 3 d are pressed by the firstintermediate transfer roller 64 a to fourthintermediate transfer roller 64 d. - Next, the intermediate
transfer belt unit 6 according to a modification of the embodiment of the present disclosure will be described with reference toFIGS. 13 and 14 .FIG. 13 is a diagram showing an example of acam 123 included in the intermediatetransfer belt unit 6 according to the modification of the embodiment of the present disclosure.FIG. 14 is a table showing a correspondence relationship between the rotation angle of thecam 123 included in the intermediatetransfer belt unit 6 according to the modification of the embodiment of the present disclosure, the operation state of theimage forming device 100, the position of the firstintermediate transfer roller 64 a, and the position of the secondintermediate transfer roller 64 b to fourthintermediate transfer roller 64 d. - The
cam 23 provided in the intermediatetransfer belt unit 6 according to the embodiment of the present disclosure is constituted by two flat cams, namely thefirst cam 233 and thesecond cam 234 as described above. In contrast, the intermediatetransfer belt unit 6 according to the modification of the embodiment of the present disclosure differs in that it includes acam 123 constituted by a single flat cam instead of thecam 23. The intermediatetransfer belt unit 6 according to the modification of the embodiment of the present disclosure has the same configuration as the intermediatetransfer belt unit 6 according to the embodiment except in that thecam 123 is provided instead of thecam 23. Therefore, the same members are denoted by the same reference numerals, and the descriptions will be omitted. - As shown in
FIG. 13 , the outer periphery of thecam 123 includes a firstperipheral edge 123 a, which is a right half outer edge, and a secondperipheral edge 123 b, which is the left half outer edge with respect to a straight line that vertically intersects thecam shaft 231 in the up-down direction. - In the
cam 123, the distance between thefirst link member 21 and thecam shaft 231 changes according to the shape of the firstperipheral edge 123 a as thecam 123 rotates. In this way, the position of the firstintermediate transfer roller 64 a can be switched according to the change in the distance between thefirst link member 21 and thecam shaft 231. - That is, when the distance between the
cam shaft 231 and the contact position betweenfirst link member 21 and the firstperipheral edge 123 a is a smallest first distance, the firstintermediate transfer roller 64 a is in the separated position. When the distance between thecam shaft 231 and the contact position betweenfirst link member 21 and the firstperipheral edge 123 a is a largest second distance, the firstintermediate transfer roller 64 a is in the pressing position. Furthermore, when the distance between thecam shaft 231 and the contact position betweenfirst link member 21 and the firstperipheral edge 123 a is longer than the first distance mentioned above, but shorter than the second distance, the firstintermediate transfer roller 64 a is in the retracted position. - Moreover, in the
cam 123, the distance between thesecond link member 22 and thecam shaft 231 changes according to the shape of the secondperipheral edge 123 b as thecam 123 rotates. In this way, the positions of the secondintermediate transfer roller 64 b to fourthintermediate transfer roller 64 d can be switched according to the change in the distance between thesecond link member 22 and thecam shaft 231. - That is, when the distance between the
cam shaft 231 and the contact position betweensecond link member 22 and the secondperipheral edge 123 b is a smallest third distance, the secondintermediate transfer roller 64 b to fourthintermediate transfer roller 64 d are in the separated position. When the distance between thecam shaft 231 and the contact position betweensecond link member 22 and the secondperipheral edge 123 b is a largest fourth distance, the secondintermediate transfer roller 64 b to fourthintermediate transfer roller 64 d are in the pressing position. Furthermore, when the distance between thecam shaft 231 and the contact position betweensecond link member 22 and the secondperipheral edge 123 b is longer than the third distance mentioned above, but shorter than the fourth distance, the secondintermediate transfer roller 64 b to fourthintermediate transfer roller 64 d are in the retracted position. - Here, a state where the first
intermediate transfer roller 64 a and each of the secondintermediate transfer roller 64 b to fourthintermediate transfer roller 64 d are in the separated position is assumed to be the initial position. When thecam 123 rotates clockwise from the initial position, as shown inFIG. 14 , the positions of each of the firstintermediate transfer roller 64 a to fourthintermediate transfer roller 64 d are switched. - Specifically, when the
cam 123 is in the initial position, or in other words, when the rotation angle of thecam 123 is 0 degrees, the firstintermediate transfer roller 64 a and each of the secondintermediate transfer roller 64 b to fourthintermediate transfer roller 64 d are positioned in the separated position. At this time, the operation state of theimage forming device 100 is detachment of the intermediatetransfer belt unit 6. - When the
cam 123 rotates 45 degrees from the initial position, the firstintermediate transfer roller 64 a and each of the secondintermediate transfer roller 64 b to fourthintermediate transfer roller 64 d are positioned in the retracted position. At this time, the operation state of theimage forming device 100 is print standby. - When the
cam 123 rotates 90 degrees from the initial position, the firstintermediate transfer roller 64 a is positioned in the pressing position, and each of the secondintermediate transfer roller 64 b to fourthintermediate transfer roller 64 d are positioned in the retracted position. At this time, the operation state of theimage forming device 100 is monochrome printing. - Furthermore, when the
cam 123 rotates 135 degrees from the initial position, the firstintermediate transfer roller 64 a and the secondintermediate transfer roller 64 b to fourthintermediate transfer roller 64 d are positioned in the pressing position. At this time, the operation state of theimage forming device 100 is color printing. - Note that the intermediate
transfer belt unit 6 according to the modification of the embodiment has a configuration in which the position of the firstintermediate transfer roller 64 a is switched by the position of the firstperipheral edge 123 a according to the rotation angle of thecam 123, and the positions of the secondintermediate transfer roller 64 b to fourthintermediate transfer roller 64 d are switched by the position of the secondperipheral edge 123 b. As a result, the rotation direction of thecam 123 is configured to be reversed when rotated by 135 degrees from the initial position. - As described above, because the intermediate
transfer belt unit 6 according to the modification of the embodiment includes thecam 123, the number of components constituting the cam can be reduced compared to the intermediatetransfer belt unit 6 according to the embodiment. However, the intermediatetransfer belt unit 6 according to the embodiment has a larger rotation angle for switching the position of the intermediate transfer rollers 64 than the intermediatetransfer belt unit 6 according to the modification of the embodiment, and the rotation angle is also a single direction. As a result, a switching control of the positions of the intermediate transfer rollers 64 can be more easily performed in the intermediatetransfer belt unit 6 according to the embodiment than the intermediatetransfer belt unit 6 according to the modification of the embodiment. - The
image forming device 100 includes an operation button (not shown), and a configuration is possible in which a detachment instruction of the intermediatetransfer belt unit 6 is received by the operation button. In such a configuration, in the intermediatetransfer belt unit 6, themovement mechanism 20 moves the positions of the firstintermediate transfer roller 64 a to fourthintermediate transfer roller 64 d to the separated position only when a detachment instruction is received. Further, when a detachment instruction is not received, a configuration is possible in which themovement mechanism 20 switches the positions of the firstintermediate transfer roller 64 a to fourthintermediate transfer roller 64 d to either the retracted position or the pressing position according to the operation state of theimage forming device 100. - In this way, when a detachment instruction is not received, the
movement mechanism 20 controls the positions of the firstintermediate transfer roller 64 a to fourthintermediate transfer roller 64 d so as to switch to either the retracted position or the pressing position. Therefore, the switching control of the positions becomes easier. - While there have been described what are at present considered to be certain embodiments of the invention, it will be understood that various modifications may be made thereto, and it is intended that the appended claims cover all such modifications as fall within the true spirit and scope of the invention.
Claims (7)
1. An image forming device comprising:
one or more image carriers on which a toner image is formed;
a transfer belt that transfers a toner image formed on the image carrier;
a presser that presses the transfer belt against the image carrier to transfer the toner image onto the transfer belt; and
a switching mechanism that switches a position of the presser according to a rotation angle of a cam; wherein
the switching mechanism switches a position of the presser to one of a first position that presses the transfer belt against the image carrier, a second position that is separated from the image carrier, and a third position that is a position separated from the image carrier and having a smaller separation distance from the image carrier than the second position.
2. The image forming device according to claim 1 , wherein
the switching mechanism, when setting a position of the presser to the first position, switches the presser from the third position to the first position.
3. The image forming device according to claim 1 , wherein
the second position is a position of the presser when the presser is detached from the image forming device.
4. The image forming device according to claim 1 , wherein
the third position is a position of the presser when the image forming device is in print standby.
5. The image forming device according to claim 1 , comprising:
a plurality of the image carriers including a first image carrier on which the toner image is formed during monochrome printing; and
a plurality of the pressers including a first presser that presses the first image carrier; wherein
the switching mechanism, during the monochrome printing, switches a position of the first presser to the first position, and also switches, among the plurality of pressers, a position of each of the remaining pressers excluding the first presser to the third position.
6. The image forming device according to claim 5 , wherein
the cam includes a first cam and a second cam that rotate by the same rotating shaft, and
the switching mechanism switches a position of the first presser according to a rotation angle of the first cam, and also switches a position of each of the remaining pressers according to a rotation angle of the second cam.
7. The image forming device according to claim 5 , wherein
an outer periphery of the cam includes a first peripheral edge and a second peripheral edge, and
the switching mechanism switches a position of the first presser based on a position of the first peripheral edge according to a rotation angle of the cam, and also switches a position of each of the remaining pressers based on a position of the second peripheral edge according to the rotation angle of the cam.
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JP2022-175905 | 2022-11-02 | ||
JP2022175905A JP2024066531A (en) | 2022-11-02 | 2022-11-02 | Image forming device |
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US20240142898A1 true US20240142898A1 (en) | 2024-05-02 |
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US18/381,827 Pending US20240142898A1 (en) | 2022-11-02 | 2023-10-19 | Image forming device |
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US (1) | US20240142898A1 (en) |
JP (1) | JP2024066531A (en) |
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- 2022-11-02 JP JP2022175905A patent/JP2024066531A/en active Pending
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